Find Matching Non-Empty Values in Different Rows and Different Columns using SQL

In this article, we will explore an SQL query that allows us to identify rows where different columns have the same non-empty values, aiding us in gaining valuable insights from our data.

The SQL Query

SELECT t1.*
FROM your_table t1
JOIN your_table t2 ON t1.column1 = t2.column2
WHERE t1.column1 <> '' AND t2.column2 <> '';

SQL Query Explanation

1. The SELECT statement retrieves the complete row information (*) from our table, your_table.
2. We utilize a self-join to connect two instances of the same table (your_table). By creating aliases t1 and t2 for the table, we can distinguish between them.
3. The ON clause defines the condition for the join. In this case, we compare column1 from t1 with column2 from t2.
4. The WHERE clause adds additional conditions:
   1. t1.column1 <> '' AND t2.column2 <> '' guarantees that the values in column1 and column2 are not empty strings, focusing our analysis on non-empty values.

Sample Table

Output with Query

Remember to adapt the query to your specific table and column names, ensuring you achieve the desired results. SQL’s flexibility allows you to harness the full potential of your data, unraveling meaningful patterns and associations in your database.